1. Field of the Invention
This invention relates generally to the field of improved fluid bearing track structures, components thereof, and methods of utilizing the same in conjunction with transferring articles, particularly fragile articles such as silicon and like wafers, between predetermined stations. More particularly, this invention relates to the field of procedures for transferring articles between stations on a fluid bearing at selectively variable rates of movement, including if desired, a full stop or dwell for predetermined periods of time, followed by rapid acceleration to a predetermined location.
Still more particularly, this invention relates to the field of high temperature fluid bearing track structures which are heat resistant and which may be incorporated into a heat treating apparatus in which articles, such as silicon and like wafers commonly utilized in the production of electronic devices, may be heat treated. This invention also relates to the field of apparatus and methods for rapidly quenching such heated articles in a procedure which insures uniformly reproducible results.
This invention further relates to the field of improved refractory type heat resistant fluid bearing track structures utilizable in heat treating devices, such as diffusion furnaces commonly and extensively utilized in the electronics industry in the manufacture of semiconductor and like electronic devices. In that regard, while in its more specific aspects, the track structure and method of this invention relate to the improved fluid bearing handling and transferring of articles utilized in the production of electronic devices, such as semiconductor wafers, its applicability in other fields in which articles are required to be automatically transported under controlled non-manual conditions at variable rates of movement also should be recognized.
2. Description of the Prior Art
Fluid bearing track structures for utilization in the handling and transfer of fragile articles, such as silicon and like wafers utilized in the manufacture of semiconductor devices, have been known heretofore, as described in the above identified Lasch et al and Lasch applications. Such prior known track structures, however, were devised for utilization generally at normal temperatures and, because of the materials from which the same are produced, such track structures are not utilizable in conjunction with article handling systems requiring transfer of articles through high temperature environments.
So far as is known, the apparatus, the particular track structure, and the transfer method disclosed herein have been unknown heretofore, and have not been used in conjunction with transferring of articles through a high temperature furnace. More particularly, so far as is known, the track structure disclosed has not been utilized heretofore in conjunction with transfer of articles at variable rates of movement, including if desired, a full stop or dwell, and a rapid acceleration.
In the electronics industry when high temperature treatment of silicon or like wafers is to be effected in a diffusion furnace or like heating devices, current practice calls for the furnace attendant to place a refractory carrier, such as a quartz block, on which a series of wafers are supported into the furnace for a predetermined time period. After the wafers have been heat treated in the furnace to accomplish the treatment desired, the furnace attendant manually withdraws the carrier block from the furnace as rapidly as possible and sets the hot carrier on a cold metal plate to effect cooling of the carrier and the wafers carried thereon. Such cooling takes several seconds, with the cooling rate varying depending upon the operator's dexterity, skill and experience. As a result, the highly necessary results of rapid cooling accompanied by reproducibility of cooling time are not achievable with the manual operations heretofore encountered. Thus, the manual methods heretofore used are incapable of producing the uniformity of results producible by the present invention.
With the present invention, transfer of articles into and out of a high temperature environment is effected automatically, sequentially and without manual handling, and the reduction of temperature of individual articles in sequence is effected rapidly so that high speed operation and reproducibility of treating results are insured with uniformity in each of a series of articles being treated in the heated atmosphere.